Wearable alarm system incorporating phased-array radar water sensing

ABSTRACT

The phased-array radar allows the remote sensing of water in either daylight or night. The phased-array radar comprises multiple antenna elements including an independent antenna element phase shifter allowing beamsteering. The device scans an object using a preset beamsteering algorithm independent of movement. The multiple antenna elements and beamsteering improve image data accuracy which is then interpreted and correlated with a body of water characteristics. The phased-array radar is also used for caretaker-monitored person communications.

This application is a continuation of U.S. Utility application Ser. No.15/479,989 filed Apr. 5, 2017, which claims priority from U.S.Provisional Application 62/390,727, filed Apr. 6, 2016. The entirecontents of the aforementioned patent applications are incorporatedherein by this reference.

FIELD

This invention relates generally to a personal alarm system that is usedto alert a user when an individual being monitored is in danger. Inparticular, a system and wearable monitoring devices aimed at preventingdrowning.

BACKGROUND

It is well established that children can easily fall into a body ofwater such as a swimming pool or wander into the ocean and end updrowning. In the past, a parent kept track of a child by holding theirhand or by tethering the child to themselves using some sort of leash,but many would view tethering as child abuse and it could be dangerousif the tether is too long allowing it to be caught, trapping the childand the parent as well in a dangerous situation.

There are different types of devices and systems that have beensuggested to avoid these tragedies but they fail to alert the child'sguardians early enough to make them effective. They also tend to becomplicated to use or too basic to provide any value. Some systems failto accurately alert to a water danger or water emergency, or fail toprovide any advanced warning of the child's proximity to the waterdanger, and tend to be limited to one body of water and are notportable.

For the foregoing reasons, there remains a need for a system to alert aparent before a child enters any large body of water providing a parentan opportunity to intervene from enough notice.

SUMMARY

It is an object of present technology to provide improvements, inparticular improvements aiming at preventing a child from dangeroussituations.

The present technology arises, in one aspect, from an observation madeby the inventor that no apparatus or device exist using technology thatgives adequate and accurate notice to a parent when that child is withinmeters of a body of water large enough to drown in or the ability torelay other information related to dangerous situations children mayfind themselves in.

The objective of the invention is to accomplish at least one of thefollowing:

-   -   to notify the parent when a child wearing the safety device is        beyond a preset distance;    -   to notify the parent when the child wearing the safety device is        close to water;    -   to notify the parent when the child wearing the safety device is        in water;    -   to notify the parent when the child wearing the safety device        has requested their help; and    -   to notify the child or children wearing the safety devices that        they are to proceed home or to a pre-agreed upon destination.

This invention is of a wearable monitoring alarm system for alerting aparent that a child may be in a dangerous situation or may be at risk ofdrowning. Although this invention refers to a parent and a child, it isalso applicable to those requiring supervision in public spaces such asthe elderly or those with special needs. For simplicity and clarity,those responsible for supervision such as a parent, a caretaker, or acustodian will be referred to as a “parent”. Those who need supervisionsuch as a child, an elderly person or a special needs person will bereferred to as a “child”.

This system notifies a parent when a triggering event occurs. Thistriggering event happens when the parent safety device becomes separatedfor greater than a pre-determined distance from the monitored child'ssafety device, or if the child is near a large body of water, or if thechild becomes immersed in water or if the child signals they are in needof help. The system also enables the parent to quickly trigger an alerton the child safety device.

The system comprises two to four identical safety devices which are eachencased in waterproof materials. One safety device is worn by the parentand a safety device is worn by each of up to three children who requiresupervision. The devices are configured during wireless setup toidentify the parent safety device and the child safety device. Thestatus of each safety device is sent and received wirelessly to alertthe parent when one or more of the children are in a dangerous situationand is communicated via a visual display of LEDs as well as audiospeakers.

The visual display of the safety devices comprises three data arrayswherein each represents one child's current safety status. The monitoredchildren's safety devices send an alert that lights up the LEDs in theirrelated data array and makes an audible tone whenever a child is beyonda selected distance, near a body of water, or in water, or if the childsignals they are in trouble.

Thus, in one aspect, a method to notify the parent when a child isbeyond the selected distance limit by employing a power detector thatdetermines when the child wearing the safety device is beyond theselected distance and then alerting the parent safety device with anaudible tone and red LED light.

Thus, in another aspect, a method to notify the parent when a child isclose to water by employing phased-array radar which uses imageprocessing to determine if the monitored child is within 1 to 2 meters(about 5 feet) of the body of water that is at least 3 meters square(about 9 square feet) in size, and then alerting the parent safetydevice with an audible tone and a red LED flashes; if the child is alsobeyond the preset distance, an addition red LED light is turned on.

Thus, in another aspect, a method to notify the parent when a child isin water by employing water sensors that when contact is made withwater, the short between the sensors results in alerting the parentsafety device with an audible tone and a red LED is turned on; if thechild is also beyond the preset distance, an addition red LED light isturned on.

Thus, in another aspect, a method to notify the parent when a childrequests help by pressing a notify button on the child safety devicewhich results in alerting the parent safety device with an audible toneand a yellow LED is turned on; if the child is also beyond the presetdistance, an addition red LED light is turned on.

Thus, in another aspect, a method to provide the parent a way to contactthe monitored child or children by pressing the notify button on theirsafety device which results in alerting all monitored children with anaudible tone from the child safety device and lighting up two red LEDs.The meaning of the notification is agreed to between the parent andmonitored children beforehand such as meeting at a designated place orto return to a home.

Communication between devices uses a wireless method wherein each childsafety device continuously transmits and receives a condition sequencecode with the parent safety device in half-duplex, preventing transmitcircuits from interfering with the receive circuits.

The present invention employs a multiple antenna element phased-arrayradar in the child safety device which uses a method to continuallysteering the beam according to a pre-defined digital image processingalgorithm independent of the monitored child's movement; interpretingthe radar reflections to identify a body of water; and sending acondition sequence code to the parent safety device.

In some implementations, the multi-element phased array radar isconfigured such that the safety devices use and can switch between a 2.4GHz band and a 5 GHz ISM band to communicate depending upon theinterference level detected by a power detector. Demodulation occursusing a digital phase-locked loop and a correlator implemented in themicrocontroller.

In some implementations, the multi-element phased array radar isconfigured to operate in the unlicensed V-Band or at a lower frequencyband.

Each safety device requires 3 W of power which is delivered by aninternal power supply within the safety device.

Additional and/or alternative features, aspects and advantages ofimplementations of the present technology will become apparent to oneskilled in the art from the following description, the accompanydrawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention, where:

FIG. 1 presents a front perspective drawing of the wearable monitoringalarm system housing of the present invention;

FIG. 2 presents a flow diagram illustrating how to set up a wearablemonitoring alarm system of the present invention;

FIG. 3 presents a flow diagram illustrating LED color interpretation andsequence codes of the present invention;

FIG. 4 presents a table illustrating the bit sequence representation ofthe present invention;

FIG. 5 presents a block diagram illustrating the phased-array radaraccording to some embodiments of the present invention;

FIG. 6 presents a block diagram illustrating the phased-array radarusing the V-Band according to some embodiments of the present invention;

FIG. 7 presents a table illustrating the frequencies used in someembodiments of the present invention; and

FIG. 8 presents a flow diagram illustrating operations according to someembodiments of the present invention.

DETAILED DESCRIPTION

The examples provided and conditional language recited here areprimarily intended to assist the reader in understanding the principlesof the present technology and not limit the scope to such specificallyrecited examples and conditions. It will be appreciated that thoseskilled in the art may devise various versions that although notexplicitly described or shown herein nonetheless embody the principlesof the present technology and are included within its spirit and scope.

Furthermore, the following description may describe relativelysimplified implementations of the present technology as an aid tounderstanding. As persons skilled in the art would understand, variousimplementations of the present technology may be of a greatercomplexity.

In some cases, what are believed to be helpful examples of modificationsto the present technology may also be set forth. This is done merely asan aid to understanding, and, again, not to define the scope or setforth the bounds of the present technology. These modifications are notan exhaustive list, and a person skilled in the art may make othermodifications while nonetheless remaining within the scope of thepresent technology. Further, where no examples of modifications havebeen set forth, it should not be interpreted that no modifications arepossible and/or that what is described is the sole manner ofimplementing that element of the present technology.

Moreover, all statements herein reciting principles, aspects, andimplementations of the present technology, as well as specific examples,thereof, are intended to encompass both structural and functionalequivalents thereof, whether they are currently known or developed inthe future. For example, it will be appreciated by those skilled in theart that any block diagrams herein represent conceptual views ofillustrative circuitry embodying the principles of the presenttechnology. Similarly, it will be appreciated that any flowcharts, flowdiagrams, state transition diagrams, and the like represent variousprocesses which may be substantially represented in computer-readablemedia and so executed by a computer or processor, whether or not suchcomputer or processor is explicitly shown.

The functions of the various elements shown in the figures, includingany functional block labeled as a “processor,” may be provided throughthe use of dedicated hardware as well as hardware capable of executingsoftware in association with appropriate software. When provided by aprocessor, the functions may be provided by a single dedicated processoror by a plurality of individual processors. In some embodiments of thepresent technology, the processor may be a general purpose processor,such as a central processing unit (CPU) or a group of cooperating CPUs,or may alternatively be a processor or a group of co-processorsdedicated to a specific purpose, such as a graphics processing unit(GPU). Moreover, explicit use of the term “processor” or “controller”should not be construed to refer exclusively to hardware capable ofexecuting software, and may implicitly include, without limitation,digital signal processor (DSP) hardware, network processor, read-onlymemory (ROM) for storing software, random access memory (RAM), andnon-volatile storage. Other hardware, conventional and/or custom, mayalso be included.

Software modules, or simply modules which has been implied to besoftware, may be represented herein as any combination of flowchartelements or other elements indicating performance of process operationsand/or textual description. Such modules may be executed by hardwarethat is expressly or implicitly shown.

FIG. 1 is a drawing that illustrates the housing of a safety device 140in accordance with an embodiment of the invention, a wearable monitoringalarm system. The safety device, which is worn by a supervising adult(such as a parent), and another identical safety device is worn by aperson who needs minding (such as a child), is shown with a front side114. The system alerts the parent when said child is beyond a selecteddistance, or is close to water, or is in a body of water, or said childsignals they are in trouble, or said parent wishes to contact saidchild. The system can monitor up to two additional children who wouldalso each wear the safety device on an arm.

The safety device 140 has a waterproof housing comprising a front piece114 and a back piece 130 of identical size and of a rectangular shape,wherein the front 114 and the back pieces 130 are separated andconnected by a set of four sides comprising a left side piece 116, a topside piece 107, a right side piece 122, and a bottom side piece 112,each of which have an equal height to separate an exterior space outsideof the housing from an interior space inside of the housing.

The front piece 114 is comprised of a visual display assembly comprisinga set of three embedded LED data array matrixes (105, 106, 108), anembedded set of buttons (102, 103, 109, 110, 113), and is connected onthe left side 116 and on the right side 122 with a waterproof wrist band111 assembly designed to be worn on the top side of the user's arm.

The wristband assembly 111 is comprised of a waterproof strap having afirst end and a second end attached to the exterior of the housingassembly at a midpoint on the left side 116 of said safety devicehousing. There is a second waterproof strap having a first end and asecond end attached at a midpoint on the exterior of the safety devicehousing on the right side 112 opposite of the first waterproof strap.The two unconnected ends of the straps are connected such that the strapis adjustable to fit different wrist sizes.

A first data array matrix 105 is located in the top left corner of thevisual display assembly on the front side 114 of the housing whichcorresponds to a first monitored child. A second data array matrix 106is located in the top center of the visual display assembly on the frontside of the housing and corresponds to a second monitored child. A thirddata array matrix 108 is located in the top right corner of the visualdisplay assembly on the front side 114 of the housing and corresponds toa third monitored child.

Each LED data array matrix (105, 106, 108) is identical and is comprisedof an electronic module that comprises two rows and three columns. Thethree columns in the first row and the first two columns in the secondrow each contain a button comprised of a water proof material such assilicone elastomer that is backlit by an LED light. Wherein the LED inthe first row and first column is green, the LED in the first row andsecond column is yellow, and the LED in the first row and the thirdcolumn is red, which can be flashed on and off. In the second row, theLED light in the first column is green, the second row and second columnis red. The second row third column contains an audio speaker foraudible alerts.

The LEDs in a data array matrix (105, 106, 108) on the receivingdesignated parent safety device light up corresponding to a specificcondition sequence code and only for the data array corresponding to thesending child device. The condition sequence codes indicate what thedangerous situation may be. An audible tone is heard from speaker on thereceiving safety device to announce a change in status whenever acondition sequence code is received.

Visible on the front side 114 as well are a set of control buttons (102,103, 109, 110, 113), each comprised of a water proof material such assilicone elastomer which are backlit, which are arranged in a matrixcomprised of two rows and three columns. The control button matrix islocated directly below the data array matrixes (105, 106, 108). Thebutton in the first column and first row 103 designates the safetydevice as a parent device during the setup process. The button in thesecond column of the first row 113 is for the parent to either notifythe children of a preset message or for a monitored child to send apanic notice to the parent. The button in the third column of the firstrow sets the distance for a child to be considered out of range 109. Thebutton in the first column of the second row is used in the setupprocess to synch 102 the parent device with a child device. The buttonin the third column of the second row provides a way to power on and offthe safety device on or off 110.

The left side piece 116 has two water sensors 101 embedded above anattached wristband 111, the top side piece 107 has four water sensors104 embedded in a row equally spaced across, and the right side piece122 has two water sensors 121 embedded in a column above the otherattached end of the wristband 111.

Contained between the front piece 114 and the back piece 130 andcontained within the set of four sides (116,107, 122, 112) of thehousing, are a set of internal systems that are comprised of anelectronic system that enables the transmit and receive functionscomprising a classical superheterodyne transceiver, an array of antennaelements with a phase shifter in each of said antenna elements, a localoscillator, an analog to digital converter (ADC), a receiver, aDSP/microcontroller, a digital to analog converter (DAC), a mixer, aphase shifter, and a clock.

In an example implementation, FIG. 5, provides a block diagram for aninternal electronic system using a 2.4/5 GHz communications comprised ofa set of RF switches, a set of amplifiers, a set of phase shifters usedwith a radar system, a set of Wilkinson power dividers that areoptimized for 2.4-5.7 GHz performance, an RF mixer (from 2.4/5 GHz to500 MHz); the intermediate frequency circuits are comprised of a set offilters, a set of amplifiers, a set of transformers, and a set of dataconverters that are optimized for the 500 MHz range, a 2.95/5.2 GHzfrequency synthesizer for a LO signal to an RF mixer for frequencyconversion in the RX and TX paths, and a separate synthesizer is usedfor a clock for the data converters.

FIG. 2 is a flow diagram that illustrates the method of setting up thewearable monitoring alarm system of the present invention. The setupmethod is comprised of:

-   -   determining whether the parent safety device is currently        powered on; if it is not already on, the power button 110 on the        designated parent safety device is pressed;    -   determining whether the child safety device is currently powered        on; if it is not already on, the power button 110 on the child        safety device being put into service is pressed;    -   pressing the SYNCH button 102 on the parent safety device and        the child safety device at the same time allowing the child        safety device to join the network; this will transmit the stored        Network identification (“ID”) and the Device ID to the child        safety device which stores the IDs, allowing the child safety        device to receive and process data from the parent safety device        as well as the parent device to receive and process data from        the child safety device; and    -   selecting an out-of-range distance; a default distance is about        55 meters (60 yards) and can be changed to a longer distance of        about 90 meters (100 yards) by pressing the range button 109 on        the parent safety device; this action generates a transmission        to the child safety device which then receives and sets the new        distance, or does nothing and uses the default out-of-range        distance; the distance can be toggled between the default        distance and the long distance by pressing the range button 109        again.

The present invention uses a method to determine the distance of thechild safety device from the parent safety device comprised of measuringthe drop in power using a power detector in the safety device,calculating the distance, and then issuing the condition sequence codeto alert the parent safety device.

The present invention uses the same method of setting up and synchingthe parent and child safety device for when a second child safety deviceor a third child safety device is added to the safety alarm system.

The present invention uses a set of antenna elements in the parentsafety device and a set of antenna elements in the child safety deviceto facilitate radio frequency transmit and receive data. A method usedfor transmitting and receiving data similar to time-division multipleaccess (TDMA) comprising transmitting in a timeslot by each child safetydevice that is determined by the order in which it was added to thenetwork on a periodic basis of every 500 μs to 50 ms. The methodminimizes collisions and interference at the parent safety devicereceiver and the child safety devices.

FIG. 4 shows the bit sequence sent from the child safety device of thepresent invention. The first four bits are for the Network ID and thenext two bits for the Device ID, which are determined during setup withthe parent safety device. The next one bit is the frequency band that isbeing used. It is determined by the child safety device based upon theamount of traffic in use over the bands. The next three bits are theCondition bits which are determined by the status of the child safetydevice at that time. The condition represents a triggering event such asthe child safety device being beyond a set distance, is close to water,is in water or the child has requested help. A last digit, a stop bit isused to signify the end of the sequence.

The flow diagram in FIG. 3 illustrates LED color interpretation andcondition sequence codes transmitted to the parent safety device of thepresent invention. The condition sequence codes sent from the childsafety device to the parent safety device is determined by theenvironment the child safety device is experiencing and whether or notthe child safety device is within range of the parent safety device. Thefirst row of each data array matrix (105, 106, 108) represents thecondition of the child safety device and the LEDs in the second row ofeach data array matrix (105, 106, 108) represent the range of the childsafety device.

For example, if the child safety device is within range and none of thetriggering events have occurred, the default bit condition sequence usedis “000”. This sequence notifies the parent safety device to turn on andor maintain the two green LEDs in the LED data array matrix (105, 106,108) for the specific child safety device that sent it using the DeviceID to determine which matrix to light up. No audible tone will be issuedas this is the representation of a default safe state for the childsafety device.

For all triggering events, the speaker in the data array matrix (105,106, 108) will issue an audible tone to alert on the parent safetydevice along with the appropriate LED lights being turned on.

For example, if a child safety device is determined to be out range bythe power detector in the child safety device and no other triggeringevent is occurring, the bit condition sequence code sent is “001” whichturns on the red LED in the first column of the second row for thatchild device's data array matrix (105, 106, 108) on the parent safetydevice and issues an audible tone alert on the parent safety device.

Another example of the present invention, when a child presses thenotify/panic button 113 on the child safety device and the device iswithin range, the bit condition sequence code sent is “100”, which turnson the green LED in the first column in the second row and turns on theyellow LED for that child device's data array matrix (105, 106, 108) onthe parent safety device and issues an audible tone alert on the parentsafety device.

Another example of the present invention, when a child presses thenotify/panic button 113 on the child safety device and the device is outof range, the bit condition sequence code sent is “011”, which turns onthe red LED in the second column second row and turns on the yellow LEDfor that child device's data array matrix (105, 106, 108) on the parentsafety device and issues an audible tone alert on the parent safetydevice.

Another example of the present invention, when the child safety devicephased-array radar system remotely senses the near proximity of waterthat covers more than about three square meters (about 9 square feet)and the device is within range, the bit condition sequence code sent is“110”, which turns on the green LED in the first column in the secondrow and causes the red LED in the first row of the parent to flash offand on for that child device's data array matrix (105, 106, 108) on theparent safety device and issues an audible tone alert on the parentsafety device.

Another example of the present invention, when the child safety devicephased-array radar system remotely senses the near proximity of waterthat covers more than about 3 square meters (about 9 square feet) andthe device is out of range, the bit condition sequence code sent is“101”, which turns on the red LED in the second row and causes the redLED in the first row of the parent to flash off and on for that childdevice's data array matrix (105, 106, 108) on the parent safety deviceand issues an audible tone alert on the parent safety device.

Another example of the present invention, when any two of the childsafety device water sensors (101, 104, 121) are electrically shortedtogether by being connected with water, the child safety devicedetermines it is submersed in a body of water. When the device is withinrange, the bit condition sequence code sent is “010”, which turns on thegreen LED in the first column in the second row and causes the red LEDin the first row of the parent safety device to turn on for that childdevice's data array matrix (105, 106, 108) on the parent safety deviceand issues an audible tone alert on the parent safety device.

Another example of the present invention, when any two of the childsafety device water sensors (101, 104, 121) are electrically shortedtogether by being connected with water, the child safety devicedetermines it is submersed in a body of water. When the device is out ofrange, the bit condition sequence code sent is “111”, which turns on thered LED in the second row and causes the red LED in the first row of theparent safety device to turn on for that child device's data arraymatrix (105, 106, 108) on the parent safety device and issues an audibletone alert on the parent safety device.

The general circuits in FIG. 5 and FIG. 6 of the present inventionrepresent a classical superheterodyne transceiver for almost error-freetransmission and reception between the safety devices. The circuits areoptimized to receive and transmit 5.7-5.75 GHz or 2.4-2.45 GHz. Thesafety system comprises a transmit (TX) and a receive (RX) circuit. TheRX and TX operation is controlled by a microcontroller/DSP.

The circuit design comprises an array of antennas to narrow an antennabeam to achieve finer resolution in the radar returns and a phaseshifter in each antenna element are independently set to effect beamsteering.

The local oscillator (LO) downconverts the RX signal to the intermediatefrequency (IF) of either 500 MHz or 550 MHz. The LO is a frequencysynthesizer which outputs 5.2 GHz when the TX/RX signal 5.7 GHz or 5.75GHz. When the system is configured for the 2.4 GHz ISM band, the LOoutputs 2.95 GHz when the TX/RX signal is 2.4 GHz or 2.45 GHz. In the RXpath, the LO at the mixer LO port downconverts the 2.4/2.45/5.5/5.75 GHzsignal to 500 MHz or 550 MHz. The filters in the design attenuateunwanted signals from nearby strong interferers and mixer spuriousproducts.

The gain in the RX chain is designed for a high dynamic range. Thereceiver has a low noise floor to receive low-power signals transmittedfrom about 91 meters (100 yards) away for a low probability of error.The receiver has a high compression point to receive signals that areclose to the receiver without creating intermodulation distortion.

The analog-to-digital converter (ADC) is clocked with 1.2 GHz frequencysynthesizer.

The receiver is designed to receive signals in a range of −117 dBm to−30 dBm.

In FIG. 5 of the present invention, a data transmission method for thesafety devices is comprised of the following:

-   -   sending a digital bit sequence from a DSP/microcontroller to a        digital-to-analog converter (DAC); the DAC outputs a        frequency-shift-keyed (FSK) modulated waveform that is either at        500 MHz for a logic 0 or 550 MHz for a logic 1 (in the 5 GHz ISM        band and the opposite in the 2.4 GHz band);    -   upconverting the DAC output by a mixer to either 2.4/2.45 GHz or        5.7/5.75 GHz; and    -   sending the upconverted signal to each of the antenna elements        which comprises a phase shifter and amplification; each phase        shifter is independently set to steer a beam in a predefined        manner to transmit to the child safety device or to scan for a        body of water.

The circuits of the present invention employ a digital-to-analogconverter (DAC) that is clocked with the same clock used for the ADC(1.2 GHz).

The present invention safety device detects water submersion using a setof sensors residing on the three of sides (116, 107, 122) of the housing114 comprised of copper and a thin chem film coating on the outward sideof the sensor to prevent corrosion. A preferred embodiment of the chemfilm coating would be aluminum chromate, or Alodine, or Iridite. Whenany two sensors are connected by water, they are electrically shortedand an approximately 50 mV is sent to an input pin on theDSP/microcontroller. The DSP/microcontroller will interpret the lowvoltage as an instance of contact with water.

The present invention parent safety device operates in anomni-directional mode continually. The omni-directional mode is enabledby setting the phase shifters in each element to 0 degrees. The childsafety device operates in an omni-direction mode when it sends status tothe parent safety device or when it senses a bit sequence from theparent safety device.

In FIG. 6 of the present invention, another embodiment of thephased-array radar operates in the V-B and (57 GHz) wherein the higheroperating frequency enables smaller patch antennas to be used creatinglower achievable beam widths and higher antenna gain. This embodimentconsists of two frequency conversions. The receiver and transmit frontend circuits are comprised of a set of RF switches, a set of amplifiers,a set of phase shifters, and a set of Wilkinson power dividers that areoptimized for 57/57.05 GHz performance. The second frequency conversionuses a V-Band mixer to convert 57/57.05 GHz to 5.7/5.75 GHz. An LO portof the mixer is driven by a 51.3 GHz frequency synthesizer output. Asecond IF created by this conversion comprising RF switches, filters andamplifiers optimized for 5.7/5.75 GHz performance.

In the present invention, the first frequency conversion creates thefirst intermediate frequency (IF). Frequency conversion occurs with anRF mixer from 2.4/5 GHz to 500 MHz. The IF circuits are comprised offilters, amplifiers, transformers, and data converters that areoptimized for the 500 MHz range.

In the present invention, the safety device transmits and receives datacommunications in half-duplex such that each safety device can transmitand receive at the same set of frequencies without the transmit circuitsinterfering with the receive circuits and without the receive circuitsinterfering with the transmit circuits. The safety device uses a powerdetector to sample the power levels to determine whether the 2.4 GHz ISMband or the 5 GHz ISM band has the lowest interference level.

In another embodiment of the present invention, the child safety devicetransmits alternatively between the 2.4 GHz ISM band and the 5 GHz ISMband on a regular basis where the demodulation will occur using adigital phase-locked loop and a correlator implemented in themicrocontroller.

In the present invention, the multi-element phased-array radar in thechild safety device continually steers the beam according to apre-defined digital image processing algorithm, which is independent ofthe monitored child's movement, to interpret the radar reflections toidentify a body of water within about 2 meters (about 5 feet) of thechild safety device and sends a condition sequence code to the parentsafety device. The phased-array radar allows the remote sensing of waterto occur either in daylight or at night since the electromagnetictransmission from a child safety device to the surroundings and thereflection from the surrounding independent of daylight. Thephased-array radar is integrated with a transceiver and operates in thesame frequency band. The multiple antenna elements and beamsteeringimproves the accuracy of the image data generated which is theninterpreted and correlated with a body of water characteristics while afirmware application controls the settings of a phase shifter in atransmit/receive module of the phased-array antenna element. Thephased-array radar is active until it detects water and sends an alert,or receives a bit sequence from the parent safety device to transmit itsstatus, or the Notify button on the child safety device is pressed, or aNotify signal is received from the parent safety device.

In the present invention, the phased-array radar shares a transceiverand operates in the 5 GHz and 2.4 GHz ISM bands wherein the phased arrayradar comprises a multiple of radar elements arranged in a square orcircular pattern wherein each radar element comprises a transmit/receivemodule connected to a patch antenna.

Another embodiment in the present invention of the phased-array radaroperates in the unlicensed V-Band or a lower frequency band and iscomprised of: a set of phased-array radar and antenna elements that havelower achievable beamwidth and higher antenna gain located in theinterior space of the housing assembly; a set of two frequencyconverters, a set of transmission circuits comprised of RF switches,amplifiers, phase shifters and optimized power dividers optimized for57/57.05 GHz performance in the interior space of the housing assembly;and a set of intermediate frequency circuits comprised of filters,amplifiers, transformers, and data converters in the interior space ofthe housing assembly.

It should be expressly understood that implementations of the system andof the method for using phased-array radar are provided for illustrativepurposes. As such, those skilled in the art will easily appreciate otherspecific implementation details for the system and for the method forprocessing data shared between safety devices. As such, by no means,examples provided herein above are meant to limit the scope of thepresent technology.

While the above-described implementations have been described and shownwith reference to particular operations performed in a particular order,it will be understood that these operations may be combined orre-ordered without departing from the teaching of the presenttechnology. Accordingly, the order and grouping of the operations is nota limitation of the present technology.

Some of these operations and signal sending-receiving are well known inthe art and, as such, have been omitted in certain portions of thisdescription for the sake of simplicity.

Modifications and improvements to the above-described implementations ofthe present technology may become apparent to those skilled in the art.The foregoing description is intended to be exemplary rather thanlimiting. The scope of the present technology is therefore intended tobe limited solely by the scope of the appended claims.

What is claimed is:
 1. A wearable safety device comprising: a) a housingassembly, b) a set of antenna elements, c) a multi-element phased-arrayradar system, d) one or more water sensors, e) a power detector, f) anotify button, g) a range button, h) a synch button, i) a power on andoff button, j) a frequency converter, k) a set of transmission circuitscomprising: i. one or more RF switches, ii. one or more amplifiers, iii.one or more phase shifters, and iv. one or more optimized powerdividers; and l) a set of intermediate frequency circuits comprising: i.one or more filters, ii. one or more amplifiers, iii. one or moretransformers, and iv. one or more data converters.
 2. The wearablesafety device of claim 1, wherein: a) the safety device is configurableas a parent or as a child device; b) the parent device communicates witha plurality of child devices; and c) each child device communicates withthe parent device.
 3. The wearable safety device of claim 1, wherein thehousing assembly is waterproof and further comprises: i. a visualdisplay assembly; and ii. one or more water sensors embedded in thesides of the housing assembly.
 4. The wearable safety device of claim 1,wherein the set of antenna elements transmit and receive conditionsequence codes: a. from the child safety device to the parent safetydevice; and b. from the parent safety device to the child safety device.5. The wearable safety device of claim 1, wherein the multi-elementphased-array radar system: a. is integrated with a transceiver operatingin the same frequency band; and b. comprises more than one radar elementwherein each radar element comprises a transmit/receive module connectedto a patch antenna.
 6. The wearable safety device of claim 5, whereinthe multi-element phased-array radar system: a. interprets radarreflections to identify a nearby body of waters sending an audible and avisual alert communication to the parent safety device when water isidentified; b. senses water in either daylight or at night; and c.operates in either the 5 GHz or 2.4 GHz ISM bands.
 7. The wearablesafety device of claim 1, wherein submersion in water: a) causes asubmersion condition sequence code to be sent from the child safetydevice to the parent safety device; and b) produces an audible and avisual alert on the parent safety device.
 8. The wearable safety deviceof claim 1 wherein the power detector determines when the child safetydevice is beyond a pre-selected distance from the parent devicecreating: a distance condition sequence code that is sent from the childsafety device to the parent safety device; and the parent safety deviceproduces an audible and a visual alert when the condition sequence codeis received.
 9. The wearable safety device according to claim 1, whereinthe frequency converter transmits and receives data: a. in half-duplexbetween each safety device at the same set of frequencies without thetransmitting circuits interfering with the receiving circuits; b. in a2.4 GHz band or a 5 GHz ISM band.
 10. The wearable safety device ofclaim 4, wherein the condition sequence code comprises: a. a 4-bitnetwork ID data which is provided by the parent safety device whensetting up and synching with the child safety device; b. a 2-bit deviceID data provided by the parent safety device when setting up andsynching with the child safety device to identify a data source when thechild safety device sends data; c. a 1-bit frequency band data set bythe child safety device; d. a 3-bit condition code which is generated bythe sending child safety device and contains status information onwhether the safety device is beyond a set distance, is near water, is inwater or said monitored child has requested help; and e. a 1-bit stopbit.
 11. The wearable safety device of claim 1, wherein pressing thenotify button on the child safety device signals the child is in troubleand causes an alert condition sequence code to be sent from the childsafety device to the parent safety device generating a visual and audioalert.
 12. The wearable safety device of claim 1, wherein thephased-array radar system further comprises: a. a set of transmissioncircuits operating in an unlicensed V-Band or a lower frequency band;and b. power dividers optimized for 57/57.05 GHz.